Vibration negatively effects safety and comfort. With regard to safety, vibration has a direct influence on stability and may cause material fatigue and damage. A main source of vibration is any rotary system of a vehicle, aircraft, watercraft or article processing machine, for example. Examples of a rotary system comprise a mechanical propulsion system comprising an engine or motor system, a power transmission system and a wheel, comprising a tyre, rim and valve, of a vehicle, such as a car, a mechanical propulsion system comprising an engine system and a rotor system of an aircraft, such as a helicopter, a mechanical propulsion system comprising an engine or motor system, a power transmission system and a propeller of a watercraft, such as a cargo ship, and a mechanical drive system comprising a motor system and drum system of an article processing machine, such as a washing machine. Vibrations may comprise rotation-speed-dependent vibrations generally originating from the engine or motor system and speed-dependent vibrations generally originating from the power transmission system. Vibrations may damage rolling-element bearings, for example ball bearings or roller bearings, used, for example, as engine bearings, or seals.
Owing to wear and tear of the rotary system, vibration generally increases over time. In more detail, owing to wear and tear of a rotating element, it's centre of gravity (CofG) moves over time causing an imbalance causing vibration.
EP patent application 0 281 252 and corresponding U.S. Pat. No. 4,867,792 disclose a thixotropic tyre balancing composition having a yield stress value between 30 Pa and 260 Pa being capable of balancing tyres by being able to flow under the influence of the vibrations induced when a heavy spot on the tyre hits the road surface. The balancing composition distributes itself in a wheel assembly consisting of a tyre mounted on a rim and having a heavy spot.
EP patent application 0 557 365 and corresponding PCT patent application WO 1992/08775 disclose a tyre gel balancing composition having a storage modulus of between 3000 and 15000 Pa, preferably its storage modulus is about 9000 Pa, is capable of balancing tyres by being able to flow under the vibrations caused by imbalance in a wheel assembly. The composition preferably comprises a mixture of: 1) paraffinic oils, polybutene oils, polyolesters or polyol ethers; 2) hydrophobic or hydrophilic fumed silica; 3) polyalkyl-methacrylates, styrene-ethylene-propylene block copolymers or polyhydroxycarboxylic acid derivatives; and optionally corrosion inhibitors and antioxidants.
U.S. Pat. No. 5,431,726 discloses a tyre gel balancing composition having a Storage modulus of between 3000 and 15000 Pa and being capable of balancing tyres by being able to flow under the vibrations caused by imbalance in a wheel assembly.
DE patent application 198 57 646 discloses a method for balancing tyres by introducing a balancing substance inside the tyre, comprising placing a substance with definite properties, shape, geometry and weight inside the tyre; and moving to the point of imbalance by rotating the tyre. The method may also be used for balancing other rotating objects.
DE patent application 198 53 691 discloses a method for introducing tyre-balancing substance as internal circumferential gel bead. The substance characteristic, shape, weight, geometry and its deposition locations are defined. The internal surface of the tyre exhibits defined shape and geometry. One or more endless strands may be employed. Strand cross section may be circular, semicircular, flattened, triangular, quadrilateral or polygonal. The one or more strands are distributed over the entire circumference, or just part of it, or both types of distribution take place. Strand portions are applied opposite the valve, when mounted on the rim. They are applied at or away from the equatorial plane, symmetrically, or else asymmetrically. The substance is injected through the valve in set quantity. A gel with a defined viscosity, thixotropy, long term stability, and compatibility with the tyre's inner surface is used. The tyre has one or more circumferential grooves, optionally between beads, to accept the substance.
PCT patent application WO 2009/037314 discloses a method of processing a vehicle tyre and a thixotropic balancing substance comprising providing a first amount of the balancing substance to a first circumferential balancing area on an inner side of the vehicle tyre comprising distributing the first amount of the balancing substance on the first balancing area substantially uniformly; and a corresponding apparatus and system. In one embodiment a varnish layer comprising nanoparticles is provided on the first circumferential balancing area to increase the movability of the thixotropic balancing substance on the balancing area.
Thus, for balancing a rotary system, such as a vehicle wheel, a rotational element, such as a vehicle tyre, comprising a chamber and a circumferential balancing area, such as an inner liner, may be partially filled with an amount of a thixotropic balancing substance.
Further, the circumferential balancing area may be provided with a nanostructure. The nanostructure may be formed during production of the vehicle tyre, requiring non-standard, special equipment. If the vehicle tyre is a standard tyre, the nanostructure may provide, in an additional production step, by distributing a material, such as a varnish, comprising nanoparticles on the balancing area. However, the varnish may comprise a solvent, and the solvent may raise an environmental concern or cause a health and safety hazard during production. Even if the varnish is water-based and does not comprise a solvent, the additional production step requiring time and involving cost is necessary.
For these and other reasons, there is a need for the invention as set forth in the following in the embodiments.